Index

Introduction

This article describes the original components and
applications for 1967-1969 Camaro cooling systems, including
radiators, radiator tanks, fan shrouds, and engine cooling
fans. It addresses how engine, transmission type, and two
options - the V01 heavy duty (HD) radiator option and the
C60 air conditioning (AC) option - affected radiator and
cooling fan selection by the factory. Note that the
information presented here applies specifically to Camaro.

All first-generation Camaro radiators were manufactured by the
Harrison Radiator Division of GM and were of the cross-flow design
type (as opposed to earlier vertical flow designs). Hot coolant from
the engine enters the upper left-hand side of the radiator and is
cooled as it passes through the radiator core, exiting the lower
right-hand side into the waterpump (RH and LH as observed from the
driver's position).

The basic cooling system design is robust and with proper maintenance,
will last for years. See JohnZ's
Cooling Basics for practical information about the proper functions
of the components and system.

Radiator Variables

Design variables in Camaro radiators included core thickness (number
of rows in the core: 2, 3, or 4), core width (21-inch or 23-inch), and
core fin spacing. Radiator heat rejection capacity improves as core
thickness and width increases and as core fin spacing decreases.
It is believed that all first gen Camaro radiators had copper/brass cores.
Some GM documentation indicates that some small block radiators had aluminum
cores, but there is no further evidence to support that assertion. All
radiators were painted gloss black and had the mounting brackets
soldered onto the radiator end tanks.

Radiators for cars with automatic transmission included a
transmission oil cooler in the passenger side end tank;
manual transmission radiators did not have this provision.
The fin spacing is also smaller for automatic radiators
(smaller fin spacing increased the radiator's heat rejection
capability) to compensate for the increased heat input from
the automatic transmission. (Note that radiators sold for
service use are often generic and include the transmission
cooler provision even for manual transmission cars.)

A heavy-duty radiator was available by ordering either of
two options. Regular Production Option (RPO) V01 was the heavy-duty
radiator option and was available with all engines except the Z28 or
big block engines. All vehicles optioned with air conditioning (RPO
C60) also received a HD radiator.

Axle ratio did not affect the radiator usage with one (unverified)
exception. In the April 1 1969 revision of the dealer ordering information,
it states that Positraction Rear Axles: Ratios 3.73 or 4.10 without
Special Performance Package (Z28) or 396 engine "also includes HD radiator"
and the MSRP is $56.90. This means that a SS350 (or L65 or 307) with 3.73 or 4.10 gears
would automatically get the V01 radiator. This would also apply to COPO 427
cars (and the higher price showed up on some later COPO window stickers),
but they already received a 4 core radiator as part of the COPO package.

Radiator Usage

The standard radiator for L6 and small block V8 engines was a 2-row
core (1.26-inches thick) that was 21-inches wide.

On all 1967-9 L6 cars, adding RPO V01 or AC resulted in use of
a radiator that differed from the standard part only by the use of a
smaller fin spacing.

For 1967 and 1968 small blocks, adding V01 or AC increased
the radiator from a 2-row core to a 3-row core (1.98-inches
thick). The V01 or AC radiators for the 67-68 L30 and L48
engines also received a wider 23-inch wide 3-row core.
But in late 68, the AC or V01 radiators for L30 and L48
engines changed to a 21-inch core instead of a 23-inch core.
We don't know the reason for this application change, but it was
consistent with the upcoming 69 usage.

For 1967 big block engines, AC was not a factor in radiator
selection since the SS396 was not available with AC in 1967.
For 1968 big blocks, AC was an available option for the L35
and L34 engines and increased the radiator from a 3 core to
a 4 core (2.70 inches thick). Note that this was a straight
neck radiator, unlike the 69 curved neck radiators that used
the same broadcast code.

For 1969, all small block radiator cores were 21-inches wide
and all big block cores were 23-inches wide. On 1969 small-block engines,
adding V01 or AC increased the size of the radiator core from 2-rows
to 3-rows. Addition of AC to 1969 big-block engines increased the
number of radiator core rows from 3 to 4 and added a curved inlet neck
in order clear the 1969 AC components. 1969 COPO 427's
(see CRG COPO
Research Report) also used this same curved-neck 396/AC 4-row core
radiator - eliminating the need for the assembly plant to stock a
straight-neck 4-core in 69.

If there was a production shortage (a relatively infrequent event),
a larger capacity radiator would be substituted.

The top and bottom plates of the original radiator core for 2, 3, and 4 cored
radiators have a unique hole pattern (the top and bottom plates are the same).
Research at Harrison Radiator by Tom DeWitt has shown that the adjacent
rectangular and square holes near the ends of the top and bottom plates were
used by Harrison to hang the assembled radiators on their paint hooks.
Most replacement cores do not have these holes. Below are two pictures
of original radiator top plates showing the hole pattern.

1969 2-Row Core Top Plate

1968 3-Row Core Top Plate

Radiator Tag Decoding

All original radiators had metal tags clipped to the header
plate of the radiator core, next to the passenger side end
tank. (When the end tank was attached, the solder would
often also solder the tag to the radiator.) The tags were
painted at the same time as the radiator and thus should be
gloss black. These tags identify the radiator via a
large-font broadcast code - a two-letter code that was used
by the assembly plant to identify parts on the assembly
line. Also stamped on the bottom edge of the tag, in a
smaller font, was the radiator part number. The 1967 tags
just had the broadcast code and the part number on it.

1967 UA and UN Tags

The 1968-1969 version of the radiator tag was larger than
the 1967 tag and added the codes for the radiator end tanks
in a smaller font next to the broadcast code. Beneath the
tank codes, is a 1 or 2 digit number that
is believed to identify the radiator core assembly to be
used in that radiator.
To the right of the core assembly number is the letter O, R, or S.
The meaning of this letter is unknown, as is the
meaning of the extra number stamped after the part number.
Note that with both 1967 and 1968/1969 tag formats, the
radiator part number may not visible when the radiator
shroud is installed and this number can be hard to read
due to the size and the depth of the stamping. The 1969 ZH
image below illustrates the various codes stamped on the
tag, including the part number on the bottom edge of the
tag.

1969 ZH Tag

The end tank codes were used by the radiator assembly plant
to identify the different tank designs and use them in the
correct radiator assembly. The month code (letters A through
M format, excluding I) is stamped on the RH end tank between
the letters of the tank code. The tank codes and applications
are shown in the table below.

A 1969 small block automatic transmission radiator tag in the
installed position on the radiator is shown below; the tag tells us
that the ZA radiator should have IH and OF end tanks. To the left of
the tag is the OF tank code and between the O and the F is the month
code, a C (for March). To the right of the tag is the clip to hold the
overflow hose from the radiator cap.

1969 ZA Tag

Radiator End Tank Codes

Side

Year

Application

Tank Code

Left Side

67-69

L6 and SB

IH

67-69

BB except 69 4-row core

IL

69

4 core BB (curved neck)

IO

Right Side

67-68

L6 and SB manual

OD

69

L6 and SB manual

CB

67-69

L6 and SB auto(exc 67-68 L30/L48 w/ V01 or AC)

OF

67-68

L30/L48 auto w/ V01 or AC - 23"

OG

69

LF7/L14 auto w/ V01 or AC

67-68

BB manual

OL

67-68

BB auto

OM

69

BB manual

OO

69

BB auto

CH

Radiator Applications

The following application data for the original radiator usage and
broadcast codes was assembled from Chevrolet documentation, original
cars, and vehicle broadcast sheets. Note that the original part numbers
listed below were often superceded by service part numbers in GM parts manuals.

Table cells colored in blue denote verified data (via cars
or broadcast sheets), while the data in uncolored cells come
from GM documentation. Cells colored in yellow denote
assumed data based on GM documentation that suggests the
listed usage. We would appreciate help with increasing the
number of table cells that are confirmed via data from
original cars.

In several applications, radiator usage changed during the
production year. Both radiator codes are noted in
the table with a reference to early or late production.

1967-1969 Radiator Applications

1967

Manual Transmission

Automatic Transmission

Engine

BroadcastCode

Part No.

CoreRows

CoreWidth (in.)

Fin Spac-ing (in.)

BroadcastCode

Part No.

CoreRows

CoreWidth (in.)

Fin Spac-ing (in.)

L26

UC

3010173

2

21

0.28

UD

3010174

2

21

0.25

L26 HD

UE

3010175

2

21

0.16

UF

3010176

2

21

0.16

L22

UA

3010171

2

21

0.22

UB

3010172

2

21

0.22

L22 V01/AC

UE

3010175

2

21

0.16

UF

3010176

2

21

0.16

LF7

UG

3010177

2

21

0.20

UF

3010176

2

21

0.16

LF7 V01/AC

UH

3010178

3

21

0.16

UI

3010179

3

21

0.16

L30

UG

3010177

2

21

0.20

UF

3010176

2

21

0.16

L30 V01/AC

UJ

3010180

3

23

0.18

UK

3010181

3

23

0.18

L48

UG

3010177

2

21

0.20

UF

3010176

2

21

0.16

L48 V01/AC

UJ

3010180

3

23

0.18

UK

3010181

3

23

0.18

Z28

UH

3010178

3

21

0.16

n/a

n/a

n/a

n/a

n/a

396

UN

3013684

3

23

0.16

UO

3013685

3

23

0.16

1968

Manual Transmission

Automatic Transmission

L26

UC

3010173

2

21

0.28

UD

3010174

2

21

0.25

L26 HD

UE

3010175

2

21

0.16

UF

3010176

2

21

0.16

L22

UA

3010171

2

21

0.22

UB

3010172

2

21

0.22

L22 V01/AC

UE

3010175

2

21

0.16

UF

3010176

2

21

0.16

LF7

UG

3010177

2

21

0.20

UF

3010176

2

21

0.16

LF7 V01/AC

UH

3010178

3

21

0.16

UI

3010179

3

21

0.16

L30

UG

3010177

2

21

0.20

UL

3016782

2

21

0.18

L30 AC/HD

UJ*

3010180

3

23

0.18

UK

3010181

3

23

0.18

ZB**

3017132

3

21

0.18

L48

UG

3010177

2

21

0.20

UL

3016782

2

21

0.18

L48 V01/AC

UJ*

3010180

3

23

0.18

UK

3010181

3

23

0.18

ZB**

3017132

3

21

0.18

Z28

UH

3010178

3

21

0.16

n/a

n/a

n/a

n/a

n/a

396

UN

3013684

3

23

0.16

UO

3013685

3

23

0.16

396 AC

UY

3016688

4

23

0.16

UZ

3016689

4

23

0.16

1969

Manual Transmission

Automatic Transmission

L26

UC

3010173

2

21

0.28

UB

3010172

2

21

0.22

L26 HD

UE

3010175

2

21

0.16

UF

3010176

2

21

0.16

L22

UC

3010173

2

21

0.28

UB

3010172

2

21

0.22

ZA

3016719

2

21

0.20

L22 V01/AC

UE

3010175

2

21

0.16

UF

3010176

2

21

0.16

L14

UA

3010171

2

21

0.22

ZA*

3016719

2

21

0.20

UL**

3016782

2

21

0.18

L14 V01/AC

ZB

3017132

3

21

0.18

ZC

3017131

3

21

0.18

LF7

UA

3010171

2

21

0.22

ZA

3016719

2

21

0.20

LF7 V01/AC

UH

3010178

3

21

0.16

ZC

3017131

3

21

0.18

LM1

UG

3010177

2

21

0.20

UF

3010176

2

21

0.16

LM1 V01/AC

UH

3010178

3

21

0.16

UI

3010179

3

21

0.16

L65

UG

3010177

2

21

0.20

UF

3010172

2

21

0.16

L65 V01/AC

UH

3010178

3

21

0.16

UI

3010179

3

21

0.16

L48

UG*

3010177

2

21

0.20

ZA*

3016719

2

21

0.20

ZH**

3020093

2

21

0.18

ZI**

tbd

2

21

tbd

L48 V01/AC

US

3014187

3

21

0.20

UR

3014186

3

21

0.20

Z28

UH

3010178

3

21

0.16

n/a

n/a

n/a

n/a

n/a

396

ZD

3017837

3

23

0.16

ZE

3017838

3

23

0.16

396 AC

UY

3018624

4

23

0.16

UZ

3018623

4

23

0.16

COPO

UY

3018624

4

23

0.16

UZ

3018623

4

23

0.16

*early production
**later production

Blue is Confirmed Data

Yellow is Assumed Data

Note: the late 68 L30/L48 V01/AC radiator is indicated in GM
documentation to change from the 23" version to the 21" 3010178
(manual) and 3010179 (auto) radiators. These usages have not been
verified. In fact, two late production 1968 manual cars with V01
have been documented with the 21" 3017132 ZB radiator.
This would suggest the radiator size did change to 21" on these applications,
but that GM documention is incorrect on which radiator was used.

Radiator Shroud Usage and Part Numbers

The following are the part numbers for the plastic fan
shrouds that were used in conjunction with the above listed
radiators. L6 engines without AC or V01 did not have a shroud,
just a small metal shield attached to the radiator support.
The L6 engine radiator shroud applications are
taken from the 1969 Chevrolet Parts Manual. It is unclear
why only some L6 HD radiators were listed as receiving a
shroud, those applications are shown in the table below.

Fan Shroud Part Numbers

Year

Application

Part Number

Notes

67-68

SB (except L30/L48 w/ V01 or AC)

3893812

67-68

L30/L48 w/ V01 or AC

3893814

23 inch

67-68

BB

3916637

69

SB

3938615

69

BB

3947619

67-69

L6 w/o V01 or AC

no shroud

used shield 3893892

67-69

L6 with AC

3893816

67

L6 with smog w/o AC

67-68

L26/manual with V01

Radiator Cooling Fans

A fixed four-blade fan was the standard engine fan on all
engines. There were two exceptions: the
solid-lifter engines (Z28, L78, and COPO 427) and vehicles
with AC used a temperature-controlled clutch fan as standard
equipment.

The temperature-controlled clutch fan was also available as
option K02 on the hydraulic-lifter engines for $15, but only
4712 1967-69 Camaros were ordered with this option. Air
conditioning (RPO C60) included the K02 clutch fan as part of the
AC package. The V01 HD radiator option did not affect
the fan usage.

Out of 400,000 non-AC V8 cars that could have
the optional clutch fan ordered, only 1% of them had the option.
Even if most of these clutch fans were installed on non-L78 SS cars
(not very likely), under 5% of those SS cars would have them.
So yes, your SS350 or SS396 (325hp or 350hp), if without AC,
likely came with the standard four-blade fixed fan.

The 1967 and 1968 V8 engines used the short water pump design
and the bolt circle diameter to mount the fan on the water pump is
1.75". In 1969, as part of the V8 engine layout standardization,
the water pump was changed to the long design and the
water pump bolt circle diameter was changed to 2.30".

Fixed (Non-Clutched) Four-Bladed Fans

The standard fixed four blade fan was 3839282 for the
1967-68 model years. It changed to 3927791 for the 1969
model, with one source indicating that 396 cars received the
3947890 fan. It is unknown what the difference is between
the two 1969 fans.

Four-Bladed Fixed Fan for 67-69

There were a number of different length spacers to mount the
fixed four-blade fan to the waterpump, as shown in the table
below. The lengths noted are the spacer length and exclude
the fan locator / pilot. Unless otherwise noted, lengths are based
on measurement of actual parts; the unconfirmed length is
from a parts manual note.

Typical Spacer for Four-Bladed Fan

Four-Bladed Fan Spacer Part Numbers

Year

Application

Part Number

Length (inch)

67-68

6 cyl.

3876828

2-9/32

67

V8 (exc. 396)

3814241

1-15/16

68

V8 (exc. 396)

3857041

1-17/32

67-68

396

3857042

1-9/32

69

6 cyl.

3927794

1-1/2

69

V8

3927792

1

Clutch Fans

The fan spacing on the clutch fans was staggered to help reduce
harmonics (and thus noise). The clutch limited the maximum speed the
fan could spin, effectively acting as a rev limiter for the fan,
reducing noise and fan power consumption.

In 1967 and 1968, the clutch fan was 18 inches in diameter, most
had five blades (there was limited usage of a seven blade fan,
see below), and came in two types:

Fan for AC or K02 cars

For 1967 cars with hydraulic lifter engines with AC or K02,
the 3789562 fan or the 912239 fan was installed. For 1968 cars
with hydraulic lifter engines with AC or K02 (except 1968 L34/L35
with K02), the 3789562 fan or the 3931002 fan was installed. The
3931002 is a seven blade fan with limited observed usage on Camaros;
it has so far been found on some LF7 (327/210hp) cars with air conditioning.
All three fans have a 3-inch diameter clutch-to-fan attachment bolt circle.
Three different fan clutch part numbers are listed as having been used
with these fans, all having the matching 3-inch diameter bolt circle.

Fan for L78 and Z28 and 1968 L34/L35 with K02

The 3871276 fan was used on the 1967 and 1968 Z28 and
L78, as well as 1968 L34/L35 with K02. The bolt circle
diameter for the clutch-to-fan attachment was
3.25-inch. It thus required a different clutch unit than the fan
clutches used with the AC or K02 hydraulic lifter engines.

Five-Bladed Fans for 67-68
(Note the difference in the center hole diameter.)

3789562 fan

3871276 fan

In 1969, the clutched fan changed to a seven-blade
design (still 18 inches in diameter) with aluminum fan blades.
Cars with AC or K02 received the same fans as the 1969 Z28 and L78/COPO
cars. There were two manufacturers of this fan and a mid-year
fan pitch change (2 to 2.25"), yielding four variants of this fan.

The 3937779 fan had a 2" pitch and was made by Schwitzer.
It was used early in the 69
production year (until approximately November of 68) and has the part
number and month / year stamped on the fan blades.

The 3947772 fan replaced the 779 fan and had a 2.25" pitch. It was
produced by Schwitzer and was used during the remainder of the production
year (and through the early 70's) and has the part
number and month / year stamped on the fan blades.

There were two versions of an 'unstamped' fan made by Hayes-Albion.
3947838 was the earlier 2" pitch version and 3956684 was the later 2.25"
pitch version. The fans are normally stamped H and FRONT, but no part
numbers or dates are stamped on the fans. They are
similar to the 772 and 779 fans but with minor design differences
(specifically: the design of the center section and details of
fan blade rivet attachment).

From what has been observed on original cars, the 3947772 fan and
the unstamped fan were used interchangeably and with approximately equal
usage. As noted above, the 3937779 fan was only used on early 69 cars.

3947772 Seven-Bladed Fan for 69

'Unstamped' Fan

3937779 Fan Close-up

One variable in the various clutch applications is the length of the
clutch unit (fan mounting surface to waterpump mounting surface distance).
Also, which clutch suppliers were used on which application may have been
dependent on the redline of the engine. Fan clutches often have the date
(Julian date and year) and part number stamped on the waterpump mounting flange.

In 1969, at least 3 different fan clutches were used for C60 (AC)
and RPO K02 cars (except 396). These cars have been observed equipped
with Delco clutch units, stamped with the broadcast code of CH.
The L35/L34 396 cars with C60 or K02 used a 3946049 clutch.
The L78/COPO used part number 3946050 (stamped CZ) and the Z28 used
3946804 (stamped CV), both were Eaton-supplied units.

1968 Z28 Fan Clutch

1969 Delco Fan Clutch

1969 Eaton Fan Clutch (CZ code)

Acknowledgments

The author would like to acknowledge the people who
contributed data on their cars, Rich Fields who originally edited
and converted this report into HTML, Rick Peters who
provided a critical page of GM documentation that was the
catalyst for completion of this long-planned Research
Report, and David Liukkonen for the details on the 69 clutched
fans.

You can help improve future revisions of this report.
We would appreciate verification of unconfirmed radiator
usages via data from original radiators and cars (or via
broadcast sheets). We also would appreciate digital photos of
original radiator tags. The tank codes on the
1968-1969 tags will help verify the radiator tank usages.